1. Field of the Invention
The present invention relates to a steam producing device for use with a steam cleaning apparatus, more particularly one, which is made in such a manner that water therein will go through dual heating processes, and which is free from the risk of explosion.
2. Brief Description of the Prior Art
Steam cleaning apparatuses are becoming popular recently, which are equipped with steam producing devices, and can eject steam produced by steam producing devices onto various objects to remove dirt, kill bacteria plus increase humidity.
Referring to FIGS. 6 and 7, a conventional steam producing device 2 of steam cleaning apparatus includes a water tank 24, a pump 23 connected to the water tank 24 by means of a conduit 244, and a steam producer 21 connected to the pump 23 by means of a duct 233; water is made to travel from the tank 24 through a water inlet 213 of the steam producer 21 by means of the pump 23. The steam producer 21 consists of a housing 211, and a heating pipe 212 disposed in the housing 211; the heating pipe 212 is connected to conducting members 218 disposed outside the housing 211 so that it can be powered to produce heat for transforming water into steam rapidly.
In order for steam to stay in the housing 211 for extended length of time so that pressure of the steam can be increased, the housing 211 is divided into a steam producing chamber, a transitional chamber 225, and a steam ejection chamber 222; the steam producing chamber is divided into a main chamber 224, and a subsidiary chamber, which is further divided into first, second, third, and fourth chambers 214, 215, 216, and 217 of the same size by means of disposing separating boards 221 in between; the main chamber 224 is half the size of the whole steam producing chamber; the separating boards 221 have steam passages 223. A steam outlet 219 is provided between the fourth chamber 217 and the transitional chamber 225 while a steam outlet 220 is provided between the transitional chamber 225 and the steam ejection chamber 222. And, the steam ejection chamber 222 is provided with several steam ejection outlets 22, which are equidistantly spaced so that steam can be ejected uniformly.
Water will become steam very rapidly after having passed into the main chamber 224 via the water inlet 213 because of the heating pipe 212. And, steam in the main chamber 224 has to pass through the chambers 214, 215, 216, and 217 via the passages 223 of the separating boards 221, and then pass into the transitional chambers 225 from the fourth chamber 217 via the steam outlet 219, and pass from the transitional chambers 225 into the ejection chamber 222 via the outlet 220 before it can be ejected from the ejection outlets 22 therefore the length of time is extended wherein steam travels through the housing 211. Consequently, pressure of steam in the steam producer 21 becomes relatively high with steam being constantly produced.
The steam producing device 2 can transform water therein into steam very rapidly, and increase pressure of steam for the same to be discharged outside the outlets 22 at high speed to remove dirt, and kill bacteria effectively.
However, the steam producing device 2 can only perform single heating cycle therefore the heating capacity is limited to some degree. And, there is risk of explosion when the steam producing device 2 is working.
It is a main object of the present invention to provide a steam producing device for use with a steam cleaning apparatus, in which water will go through dual heating processes, and which is free from the risk of explosion.
The steam producing device includes a strong outer shell, and a heating member inserted in, and secured to the outer shell. The heating member has a steam room, and forms a first, a second, and a third chamber together with the outer shell. The second chamber communicates with the first chamber owing to a gap, and communicates with the third chamber owing to a narrow curved passage provided between the heating member and the outer shell. A hole is formed on the heating member for the steam room to communicate with the third chamber. Thus, water and steam can travel through the chambers to go through one heating process, and then travel through the steam room to go through another heating process to be transformed into steam and discharged outside the shell for use after flowing into the first chamber; water and steam will undergo compression and expansion to have increased pressure when traveling through the gap and the narrow passage.